Are you trying to register/activate the software off line?
Depending on the version of Music Studio there may be the option to register offline, in this case as you work through the dialogs you will be given the option to generate the computer id, which is a combination of several factors which make up a unique ID for Magix, and instructions of what to do.
For 'in program' online activation the computer id is created automatically and you never see it.
Unfortunately, your first post here concerns a product in the Magix Vegas line. Hence you have posted to the wrong forum, sorry, and your post has been hidden. Please read this pinned post and follow the advice there to go to the correct forums.